1. Neuroscience Series Ion Channels in Rat Gonadotropin-Releasing Hormone Neurons(1)

Abstract

To understand neural mechanisms of reproductive physiology, we have generated promoter transgenic rats for gonadotropin-releasing hormone (GnRH) neurons. Using these rats we have analyzed ion channels expressed in rat GnRH neurons by means of patch clamp experiments and reverse transcriptase-polymerase chain reaction. The study revealed that rat GnRH neurons exhibit voltage-gated Na⁺, K⁺ and Ca²⁺ currents. There are delayed rectifier K⁺ currents, large conductance voltage- and Ca²⁺ -activated K⁺ currents (BK currents carried through BK channels) and Ca²⁺ -activated K⁺ currents (slow afterhyperpolarization currents carried through SK channels). Ca²⁺ currents are carried through five different Ca²⁺ channels, namely L-, N-, P/Q-, R- and T-types. Activation of these ion channels determines excitability of GnRH neurons and their firing pattern of action potentials.